The DNVGL-RP-F105 guidelines provide essential techniques for the preliminary design of undersea pipelines. However, its approximations for static displacement and the natural frequency of the pipe are restricted to cases where the ratio of the pipe’s diameter to its length (L/D) is less than 140. This limitation poses challenges for longer spans, which, although rare, can sometimes be unavoidable. This study introduces a novel analytical method, rooted in the energy method and cable theory, for computing the static deformation and natural frequency of long free-span underwater pipelines. We conducted a comprehensive verification of our proposed method by comparing its outcomes with those of 212 finite element analysis simulations. The results reveal excellent predictions for long spans. However, for shorter spans, traditional methods remain more accurate. Additionally, we explored the influence of pipeline’s diameter, thickness, and boundary conditions on both static displacement and frequency, providing valuable insights for design considerations. We found that the boundary conditions’ impact on the fundamental frequency becomes negligible for long spans, with up to a 10% difference between pinned–pinned and fixed–fixed conditions. In essence, this research offers a vital enhancement to the existing DNV guidelines, becoming particularly beneficial during the preliminary design phases of pipelines with L/D ratios exceeding 140.

Unlike the flat base foundations, the determination of the bearing resistance of the cone‐shaped footing in finite element analysis (FEA) might not be carried out without considering the interface model. In addition, the simulations of the FEA is hardly achieved with a large system due to the assembly technique. So, the alternative should be considered. Therefore, this paper proposes a new method for computing the , and factors of the bearing capacity of the rough and smooth cone‐shaped foundations by combining the skew boundary condition as the interface model incorporated with the viscoplastic strain method‐based meshfree obeying the yield equation of the Mohr‐Coulomb (MC). Thus, the factors can be determined exclusively and reported to reach a close agreement with the published data; nevertheless, the discrepancies are also provided. The plastic flow of the soil mechanics is discussed thoroughly. In addition, the effects of soil friction angle (ϕ) and cone‐shaped angle (β) on the factors are inspected systematically. Accordingly, the conservation of the Terzaghi's superposition assumption is confirmed, and the bearing capacity factor charts can be established for various combinations of 5^o – 45^o and 30^o – 180^o. Therefore, it may conclude that the results produced by these techniques and the techniques themselves may be applied confidently for solving geotechnical problems, especially for computing the bearing resistance of the soil.

This paper introduces an efficient and automated computational framework integrating Python scripting with Abaqus finite element analysis (FEA) to investigate the structural behavior of long free-spanning submarine pipelines equipped with buoyancy modules. A comprehensive parametric study was conducted, involving 1260 free-spanning submarine pipeline models, and was successfully performed with a wide range of parameters, including the length ($l_p=$ 100, 200, and 300 m), radius ($r_p=$ 0.3, 0.4, and 0.5 m), thickness, type of fluid, type of support, load ratio ($LR=$ 0.2, 0.4, 0.6, 0.8, and 1), and number of buoyancy modules ($n=$ 0, 1, 2, 3, 5, 7, and 9) with its length $(l_b=1/10·l_p)$. The study included a verification process, providing a verification of the presented framework. The results demonstrate excellent agreement with analytical and numerical solutions, validating the accuracy and robustness of the proposed framework. The analysis indicates that pipeline deformation and natural frequency are highly sensitive to variations in buoyancy arrangements, pipeline geometry, and load conditions, whereas the normalized mode shapes remain largely unaffected. Practical implications include the ability to rapidly optimize buoyancy module placements, reducing resonance risks from vortex-induced vibrations (VIVs), thus enhancing the preliminary design efficiency and pipeline safety. The developed approach advances existing methods by significantly reducing the computational complexity and enabling extensive parametric analyses, making it a valuable tool for designing stable, cost-effective offshore pipeline systems.

Due to the uncertainty that stems from the heterogeneous nature of geological materials, probabilistic tools have been incorporated into geotechnical practice. A notable example is the Monte Carlo analysis method that is available as a built-in feature in the program RS2 (Rocscience in Phase2 version 6.020. Rocscience Inc. Toronto, 2007). In this paper, we demonstrate how to utilize the Monte Carlo method for enhancement of geotechnical analysis. The procedure consists of two primary stages: 1) data generation, where numerous finite-element (FE) models are generated based on an estimated range of input parameters, and: 2) data analysis, where machine-learning models are used to correlate input parameters and results of interest. The verified ML algorithm can be referred to as a surrogate model. An example of the implementation of a surrogate model is illustrated through an anchored sheet pile wall problem. For this problem, the surrogate model correlates between the forces in the first and second row of anchors, thus allowing for prediction and optimization of ground support during construction.